Problem: Last Monday, Luis's parents gave birth to twins and named them Kevin and Gabriela. When they were first born, Kevin weighed 6.42 pounds and was 21.5 inches tall, and Gabriela weighed 8.95 pounds. How much did the babies weigh in total?
Explanation: To find the weights of the 2 babies, we need to add their weights together. Kevin's weight + Gabriela's weight = total weight. ${6}$ ${4}$ ${2}$ ${8}$ ${9}$ ${5}$ ${+\vphantom{0}}$ ${7}$ ${3}$ ${5}$ ${1}$ Together, the babies weigh 15.37 pounds.